Rock-drill.



PATENTED APR. 24, 1906. A. H. GIBSON.

ROCK DRILL.

APPLIOATION FILED AUG. 2s, 1905.

UNITED STATES PATEN T OFFICE.

ARTHUR H. GIBSON. OF EASTON. PENNSYLVANIA, ASSIGNOR TO THE INGERSOLL-SERGEANI DRILL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF IVES'I VIRGINIA.

ROCK-DRILL.

Specification of Letters Patent.

Patented April 24, 1906.

Application filed August 26,1905. Serial No. 275,851.

To LH whom, t ncty concern:

Be it known that l, ARTHUR II. GIBSON, a subject of the King of Great Britain and Ireland, and a resident of Easton, in thecounty ot' Northampton and State of Pennsylvania, have invented a new and useful Improvement in Rock-Drills, of which the following is a specification.

My invention consists in certain improvements in that class of rock-drills in which the drills are operated by reciprocating columns of air.

The object of my invention is to provide manually-operated means for accuratel adjusting theair-pressure in the tail-rod c amber ot' the drill, whereby the operation of the drill is facilitated.

In the accompanying drawings, Figure 1 represents my improved rock-drill in longitudinal central section with the drill-piston at a point intermediate the limits of its reciprocating movements. Fig. 2 is a detail longitudinal central section, on a greatly-enarged scale, of the vent-screw; and Fig. 3 is a top lan view of the vent-screw.

T e shell of the drill is denoted by l.

The cylinder is denoted by 2, its front head by 3, and its rear head extension by 4.

The piston=head of the drill is denoted by 5, its hollow tail-rod by 6, and its front rod by 7. This front rod extends through the front head 3 of the drill and is provided with the usual chuck S for the attachment of the drilltool thereto.

The cylinder is adjusted along the shell 1 by the usual screw 9, mounted to rotate in a cross-bar 10 of the shell and turning in a traveling nut 11, carried by the drill-cylinder casing.

The rifle-bar is denoted by 12 and is mounted, as is usual, at the rear of the rear extension 4. The said bar extends forwardly into the interior of the hollow tail-rod 6 of the drill-piston and is there engaged by a nut 13, fixed to the tail-rod. This tail-rod is of substantially the same diameter as the front rod 7 and is fitted to slide in a sleeve 14, spaced from the inner walls of the rear extension 4, so as to form an annular space 15, which space is connected with the space 16 back of t ve tail-rod through one or more holes 17 in the sleeve 14, the two spaces I5 and 16 thereby forming a tail-rod chamber. A small vent opening or aperture leadr from the tail-rod chamber to the external atmosphere as follows: A vent-screw 1S' is screwed into the rear extension 4, which screw is provided with a tapered hole 19 therethrough. For the purpose of accurately adjusting the size of the vent opening or aperture from the tail-rod chamber to the external atmosphere, I provide a tapered plug or pin 20, having one side flattened, as shown at 2l, which plug or pin is driven into the tapered bore 19 of the vent-screw. Bv providing a number of these pins 20, each with a different amount of flattened surface, I am enabled to accurately adjust the size of this vent-opening to different presser-pressures. I t will be seen that when it desired to change the size of this vent-opening the screw 18 may be removed from the rear extension and the plug or pin 20 knocked out of the same and another plug with the required flattened surface driven in and the screw again engaged with the rear extension. A washer 22 is located between the end of the sleeve 14 and the rotation device lor the riflebar for preventing the leakage of air therethrough. Another washer 23 surrounds the tail-rod 6 at the rear end of the piston-chainber 24 at the front of the hollow sleeve 14 for prevent-ing to as much a degree as ossible the leakage of air from the piston-c amber 24 into the tail-rod chamber. Ports 25 26 open into the piston-chamber 24 at short distances from the ends of the chamber, the

port 25 being connected to a fluid-pressure pipe 27 and t-he port 26 being connected to a fluid-pressure pipe 2S, through which the columns of air are`reciprocated by the use of a presser, not shown herein.

I provide manually-operated means for accurately controlling the pressure of air in the tail-rod chamber as follows: A passage leads `trom one of the Huid-pressure pipes 27 2S, in the present instance the fluid-pressure pipe 28, to the annular space 15 of the tail-rod chamber, which passage ia the present instance is formed by means of a short pipe connection 29, having one end opening into the pipe 28and the other end into the said tail-rod chamber. In this pipo I provide a manually-operated valve 30, so that the amount of air which shall be permitted to escape from the fluid-pressure ipe 28 to the interior of the tail-rod cham er to raise the pressure in the tail-rod chamber to the de- IOO IOS

sired degree may be controlled to the most accurate degree.

In practice I find it desirable to give the tail-rod chamber a total capacity of about twice that of theyvolume displaced by the tail rod7 so that when the tail-rod is moved into the chamber to the limit of its rearward movement there is still about half of the volume of the tail-rod chamber unoccupied. The mean pressure of this tail-rod vchamber above atmospheric pressure depends -on the amount of air which is leaking past the washer 23 and the amount of air which is permitted to leak to the external atmosphere through the ventopening hereinabove described. This pres, sure varies between zero and the mean Huctuating pressure, in the pipe 28, depending entirely on'the amount of leakage at the two points above referred to. By providing a passage' from the Huid-'pressure pipe 28 to the tail-rod chamberand' locating therein a manuallyfoperated valve I am enabled to produce a device in which the amount of airpressure inthe tail-rod chamber may be accurately adjusted to the desired point to obtain the best result in-the operation of the drill-piston.

vBy the construction andarrangement of the parts 'as herein set forth I am enabled to obtain a great percussive blow of the drill, for the reason that the compressionof air in the tail-rod chamber during the rear stroke of the.`drillpiston will act as a strong elastic spring to force the tail-rod of the piston toward the work. This force acts conjointly with the regular pressure piston from, the presser. ypneumatic spring acting against the tail-rod the drill-piston would simply have a powerful reciprocating action with comparatively poor percussive force;I It will be seen that by the use of the manually-operated valve in the passage leading from one of the fluidpressure"pipes to the tail-rod chamber I am enabled to obtain to the greatest exactitude the amount oi' pressure in the tail-rod chamber which will produce the best result on the drill-piston tailrod. It is to be understood that this manu-l ally-operated valve is only open to a'. very small degree, and slight variations in its amount of opening materially affect the op* eration of the drill.

What I' claim is- V1. A rock-drill piston having a'tail-rod,V a

cylinder having a tail-rod chamber;v and pipes for feeding the motive iluidto the oppositel sides of the piston, said cylinder having a passage leading from one of the motive-Huid pipes to thetail-rod chamber.

2. A rockedrill piston having .atail-rod, a cylinder having atail-rod chamber,ppes for feeding motive iiuid to the opnositesldes of the piston, said cylinder havin(T a. passage leading from one of the mot-ive-uid pipes to on the back of the Were it not for thisv the tail-rod chamber and manually-controlled means for regulating the flow of'air through said passage. K

'3. A'rock-drill piston having va tail-rod, a cylinder having an extension provided with ing leading from said chamber to the external atmosphere, and motive-liuid-pressure pipes for the cylinder, said cylinder having a passage leading from one of said pipes to the tail-rod chamber.

4. A rock-drill piston having a tail-rod, a cylinder having an extension provided with va tail-rod chamber and having -a vent-opening leading from said chamber vto the external atmosphere, motive-fluid-pressure pipes for the cylinder, said cylinder having -a passage leading from one-ofl said pipes to the tailrod chamber and a manually-operated valve in said passage for controlling the 'flow of air from the pipe to the chamber.

5. A rock-drill piston having a .tail-rod, a cylinder having an extension provided with a tail-rod chamber and having a ventopening leading from the chamber to 'the external atmosphere including a yscrew having a -ta- -a tail-rod chamber and having a vent-openpered bore and a pin removably yengaged with the bore, said pin having a flattened side.

6. A tool-piston, having a front rod and a tail-rod, a cylinder having-a tail-rod chamber, pipes for feeding motive iin-id alternately to the opposite sides of the piston and means for bringing the tail-rod chamber `into open communication with one of the pipes.

7:' A tool-piston Ahaving a fnont rod and a tail-rod, a cylinder having a tail-rod chamber, pipes for feeding motive fluid alternately to the opposite -sides of the piston and'means for bringing the tail-rod chamber into open communication with the pipe which effects the forward stroke of the tool.

8. A tool-piston having -a front rod and a tail-rod, a cylinder having a tail-'rod chamber, pipes for feeding motive fluid alternately to the opposite sides of the piston and a manually-operated valve for bringing the tail-rod chamber into and out of open communication with one of-said pipes.

9. A tool-piston having a front rod and 'a tail-rod, a cylinder having a tail-rod chamber, pipes for feeding mot-ive fluid alternately to the opposite sides of the piston` and a manually-operated valve for bringing the tail-rod chamber into and out of open communication with the pipe which edects the forward stroke of the tool.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this '23d day of August, 1905.

ARTHUR H. GIBSON.

IOO

IIO

Corrections lin Letters Patent. No. 818,681.

It is hereby certified that inty Letters Patent No. 818,6S1, granted April 24, 1906, upon the application of Arthur Gibson, of, Easton, Pennsylvania, for an improvemeut in Rock-Drills, errors appear requiring correction, as follows: In the specilication and claims the Word presser Wherever it occurs should read presser and the I word pressers should read pressors; and that said Letters Patent should be read with these corrections therein that the saine may conform to the record of the case in the Patent Ofhce.

Signed and sealed this 15th day of May, A. D., 1906.

F. I. ALLEN,

Commissioner of Patents.

[SEAL] 

